From 54764bb647b2e847c512acf8d443df965da35000 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 31 Jul 2012 01:08:23 +0000 Subject: ipv4: Restore old dst_free() behavior. commit 404e0a8b6a55 (net: ipv4: fix RCU races on dst refcounts) tried to solve a race but added a problem at device/fib dismantle time : We really want to call dst_free() as soon as possible, even if sockets still have dst in their cache. dst_release() calls in free_fib_info_rcu() are not welcomed. Root of the problem was that now we also cache output routes (in nh_rth_output), we must use call_rcu() instead of call_rcu_bh() in rt_free(), because output route lookups are done in process context. Based on feedback and initial patch from David Miller (adding another call_rcu_bh() call in fib, but it appears it was not the right fix) I left the inet_sk_rx_dst_set() helper and added __rcu attributes to nh_rth_output and nh_rth_input to better document what is going on in this code. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/ip_fib.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/net/ip_fib.h') diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h index e69c3a47153d..e521a03515b1 100644 --- a/include/net/ip_fib.h +++ b/include/net/ip_fib.h @@ -81,8 +81,8 @@ struct fib_nh { __be32 nh_gw; __be32 nh_saddr; int nh_saddr_genid; - struct rtable *nh_rth_output; - struct rtable *nh_rth_input; + struct rtable __rcu *nh_rth_output; + struct rtable __rcu *nh_rth_input; struct fnhe_hash_bucket *nh_exceptions; }; -- cgit v1.2.3